Method and system for LASER machining

ABSTRACT

The invention provides a method of rapidly machining multiple, often similar or nearly identical, features using a LASER machining system. During LASER machining, light of a wavelength and intensity that will modify the workpiece to be machined is directed at the workpiece and interacts to produce the desired change. If several features are to be machined, the processing speed can be increased by operating on a multiplicity of features at once. In one embodiment of the invention, this is achieved by separating the LASER beam into multiple beams and machining the desired features simultaneously.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.60/723,382, filed Oct. 3, 2005, which application is incorporated hereinby reference noting that the current disclosure governs with respect toany differences with the provisional application.

FIELD OF THE INVENTION

The present invention relates to methods of and systems for LASERmachining. More specifically, it relates to increasing processing speedand quality by multiplexing a LASER machining beam in either space ortime while measuring a response and modifying the operating parametersof the multiplexed beams.

BACKGROUND OF THE INVENTION

In different areas of technology it is desirable to make use of a thinsheet of material which has an array of regularly spaced, very smallholes therein. For example, such might be used in the manufacture ofvarious electronic components. Thin sheets which have one or more holesin them could also be used in the formation of components used in inkjet printers or fuel injectors. A more direct application of such a porearray is as a filter. The pore size and pore density could be adjustedto wide range of filter applications. Alternatively, liquid formulationscontaining a drug could be moved through such a porous member to createan aerosol for inhalation.

One of the gentlest and most acceptable methods of administering anagent to a patient is via aerosol. Aerosol therapy can be accomplishedby aerosolization of a formulation (e.g., a drug formulation ordiagnostic agent formulation) and administration to the patient, forexample via inhalation. The aerosol can be used to treat lung tissuelocally and/or be absorbed into the circulatory system to deliver thedrug systemically. Where the formulation contains a diagnostic agent,the formulation can be used for diagnosis of, for example, conditionsand diseases associated with pulmonary dysfunction.

In general, aerosolized particles for respiratory delivery have adiameter of 12 micrometers or less. However, the preferred particle sizevaries with the site targeted (e.g., delivery targeted to the bronchi,bronchia, bronchioles, alveoli, or circulatory system). For example,topical lung treatment can be accomplished with particles having adiameter in the range of 1.0 to 12.0 micrometers. Effective systemictreatment requires particles having a smaller diameter, generally in therange of 0.5 to 6.0 micrometers, while effective ocular treatment isadequate with particles having a diameter of 15 micrometers or greater,generally in the range of 15-100 micrometers.

U.S. Pat. Nos. 5,544,646, 5,709,202, 5,497,763, 5,544,646, 5,718,222,5,660,166, 5,823,178 and 5,829,435 describe devices and methods usefulin the generation of aerosols suitable for drug delivery. These devicesgenerate fine, uniform aerosols by passing a formulation through anozzle array having micrometer-scale pores as may be formed, forexample, by LASER ablation.

Pore arrays having such small features can be difficult and costly tomanufacture. Additionally, the pores must be of high quality anduniformity where they are to be used (1) in manufacturing electroniccomponents; (2) in filter materials; (3) in ink jet printers; (4) infuel injectors; and (5) to create aerosols for delivering therapeuticagents to patients in order to insure that the patients consistentlyreceive the therapeutically required dose. Consequently, there is a needfor a fabrication method and an inspection method which can rapidlymanufacture and analyze porous samples of small dimensions to determinevarious parameters including pore size and pore density, and with theability to adjust such parameters to produce a pore array having highquality and uniform pores. In the preferred embodiment, the manufactureand analysis are done simultaneously by monitoring the beam as it drillsthrough the part.

In most cases it is desirable to increase the rate at which a processcan produce output. Although this invention was developed in part by anevaluation of LASER drilling microscopic holes, nothing in themotivation, analysis, or applications necessarily limits the scope todrilling, micromachining, or even to LASER processing.

Presently, LASERs are used to drill holes in a variety of materials fora variety of purposes. In particular, ultraviolet LASERs are used todrill micro-vias in multi-layer electronic circuits and in polymer filmsfor such applications as ink-jet printer nozzles (cf U.S. Pat. No.4,508,749) and aerosol drug delivery. This process is frequentlyimplemented using an excimer LASER and a mask and projection system todrill multiple holes at once.

There are several disadvantages to this approach. Excimer LASERsgenerally have intensive energy and utility (cooling and venting)requirements, and the incoherent nature of the beam makes mask andprojection the most viable method of multiplexing the beam. The use of amasking system usually involves discarding much of the LASER energy, andin many cases of LASER hole drilling as much as 99% of the LASER poweris stopped by the mask and not used for the drilling process. Inaddition, the non-uniform output beam generally seen with excimer LASERsusually requires the use of homogenizers, and even then this technologyhas uniformity limitations.

It is difficult to drill holes with exit diameters less than 1micrometer using the process as described in U.S. Pat. No. 4,508,749. Animprovement to this process was introduced in U.S. Pat. No. 6,624,885and U.S. Publication No. US-2004-0070754-A1, published Apr. 15, 2004that allows smaller holes to be drilled. It is difficult to achieve goodbeam homogeneity across excimer LASER beams, and beam power variationscan also be introduced when multiplexing other types of LASERs. Thus,this control method faces limitations in feature-to-feature(hole-to-hole) uniformity within multiple feature arrays machined in asingle operation.

Although the feedback control method of U.S. Pat. No. 6,624,885 can beapplied to a process that drills only one hole at a time, this seriouslylimits the production speed of such a process due to the requirement tostep the target or beam from hole to hole, and then allow for settlingtime.

The process with feedback control implemented might be sped up in one ofat least three ways without fundamentally changing the process. The rateof LASER pulsing can be increased, the time to step from one feature tothe next can be decreased, or the number of features machined at oncecan be increased with individual feedback applied to each of thefeatures. Although excimer LASERs are limited to a few hundred pulsesper second, some solid-state UV LASERs (Lambda Physik Gator, CoherentAvia) can pulse as many as 100,000 times per second or more. This couldresult in speeding the process up by more than 100 times. However, italso reduces the time between pulses from more than 1 millisecond toonly 10 microseconds. Some LASER drilling processes produce a smallcloud of plasma with each LASER pulse and it may be that this plasmacloud, if not allowed time to dissipate, will modify the drillingprocess by attenuating or reflecting the LASER beam.

It may be more desirable to maintain the rate at which pulses reach eachfeature but increase the number of features drilled at the same time.However, as this discussion indicated, spatially multiplexing the beamcan result in non-uniformity between the individual features within themultiplicity, and it can be difficult to control the characteristics ofthe individual features. It is possible to use a detector with spatialresolution to monitor the progress of the process for each feature.However, for the nozzles used in aerosol drug delivery, this may requireindependently controlling hundreds of LASER beams based on the feedbackfrom a detector with hundreds or thousands of elements. In addition,machining a large array at once may in itself lead to plasma shieldingeffects. Despite these difficulties, a dynamic beam-splitter based on anacousto-optic modulator driven at many frequencies at once could splitthe beam into dozens or hundreds of beams, and the individual beamscould be turned on or off (based on information from a feedbackdetector) by modifying the multi-frequency drive signal. This methodcould be used independently or in combination with the other methodsdisclosed and described here.

A large improvement in fabrication time can be achieved by rapidlyswitching a single beam from one feature to another. Using standardstaging to move a target piece from one feature to another can requireon the order of 100 ms to move and settle, and as a result, machining apart such as a nozzle array containing hundreds of nozzles can take onthe order of a minute to complete. This time can be reduced to a fewseconds by using galvanometer mirrors, or galvos. Acousto-opticmodulators (AOMs) are capable of moving a beam from one position toanother in approximately 1 micro-second, and can be used to reduce theamount of time moving between features to a negligible fraction of thefabrication time. Two dimensional arrays of features can be fabricatedby using two galvos, two AOMs, or in a preferred embodiment, one AOM andone galvo. In addition, the progress of the individual holes can bemonitored with a detector and the drilling process can be adjusted orterminated based on this monitoring. For example, the detector can beplace behind the part being modified, and when the beam has created athrough hole, a property of the LASER light transmitted through thepiece, for example its intensity, can be measured, and the process canbe modified or terminated based on this measurement. The detector canhave a temporally resolved response so that the properties of eachsequential pulse can be determined, and then the process can be adjustedor terminated for that hole when appropriate.

The number of features being machined can also be increased bymultiplexing the drilling operation in time, directing sequential LASERpulses at the multiplicity of features to be machined. For instance, aseries of 100 pulses from a 100,000 kHz pulse train can be directedsequentially at a series of 100 holes to be drilled, and then theprocess can be repeated. In this example, each individual hole receivespulses at only 1 kHz, allowing time for the plasma cloud to dissipatebefore the next pulse. An advantage of this is that the beam can bescanned continuously, rather than in step and repeat fashion,eliminating the time delays associated with acceleration, deceleration,and settling. In addition, the progress of the individual holes can bemonitored with a detector and the drilling process can be adjusted orterminated for each hole individually. The detector can have atemporally resolved response so that the properties of each sequentialpulse can be determined and associated with the feature at which thatpulse was directed, and then the process can be adjusted or terminatedfor that hole when appropriate. Alternatively, the detector can have aspatially resolved response so that the progress of the drilling at eachlocation can be determined. In either case, once a hole is determined tobe substantially complete, the pulses that would continue to drill thathole can be omitted from the LASER pulse train.

Implementing this control scheme requires: a method of scanning theLASER beam (that is, directing sequential LASER pulses at sequentialfeatures), a method of detecting the progress of drilling on theindividual holes, and a controller that analyzes the detection,synchronizes the pulses, scanning and detection, and a controller togenerate and omit pulses and control the scanning of the beam as needed.

A number of types of high-speed scanning systems exist. LASER printerstypically use a spinning polygonal mirror to scan a LASER beam acrossthe print copy thousands of times per second. Many LASER machiningsystems use mirrors mounted on high-speed galvanometers to scan themachining LASER beam across the work piece at similar frequencies.Acousto-optic modulators, already used for spectrometers, LASERQ-switches, and some LASER scanning systems can achieve even higherfrequencies.

Aspects of spatially multiplexing LASER beams used for processing isreferred to in U.S. Pat. No. 6,625,181 which uses a fixed beamsplitterconfiguration, beam modulation after beamsplitting without feedback.

SUMMARY OF THE INVENTION

A method of machining a component is disclosed. The method firstinvolves creating an energy beam which may be a LASER beam or otherenergy beam capable of processing a component. The energy beam or LASERbeam is then split into a plurality of sub-beams. The sub-beams arefocused on individual features of a component to be machined. A sensoris used to detect energy from the sub-beams which are focused on thefeatures. By analyzing the energy detected by the sensor it is possibleto create a signal, such as signal of digital information. The signal issent to a device which controls the energy beam or LASER beam andthereby controls the machining of the component. For example, when thesensor detects that a sub-beam has drilled a hole of the pre-specifiedquality, for example size of opening, shape and depth, into a component,the LASER is deactivated or the sub-beam used in creating that featureis discontinued.

A part to be modified by a LASER process or other energy source can beprocessed more rapidly and precisely by modifying the process in one ormore of the following ways: (1) directing the LASER beam at more than asingle feature while features are being processed, (2) decreasing theamount of time required to move the beam from feature to feature, (3)increasing the amount of power delivered to the part, preferably byincreasing the repetition rate of a pulsed (q-switched) LASER withoutchanging the properties of individual LASER pulses (4) detecting theprogress of the process on individual features or subgroups of features,(5) analyzing the progress detected, and (6) modifying or terminatingthe process on individual features or subgroups of features in responseto the information obtained by monitoring the progress of the process.

The system implementing this must have (1) a LASER controller thancauses the LASER to operate appropriately for the process, (2) a beamsplitter or scanner to direct the beam at a multiplicity of featureseither (a) simultaneously or (b) sequentially, (3) a detector to monitorthe progress of the LASER processing on the individual features orsubgroups of features, (4) an analysis apparatus, circuit, or computerto convert the detected information into an appropriate change in theprocess parameters for those individual features or subgroups offeatures, and (5) a synchronizing control system that can apply thechanges to the processes applied to those individual or subgroups offeatures.

A method of machining is disclosed. The method comprises sequentiallyapplying energy to a multiplicity of areas where a feature is to bemachined into the area and repeating the sequential application ofenergy to the area thereby allowing a multiplicity of features to bemachined into the multiplicity of areas essentially at the same time.Although different types of energy beams may be used a LASER ispreferred and particular types of LASERs are preferred in particularsituations.

In another aspect of the invention the method is carried out wherein theLASER is directed from one area to another area by an element chosenfrom a spinning element, a vibrating element and an oscillating element.The spinning element may be a polygonal mirror. The oscillating elementmay be an oscillating optical element and the oscillating opticalelement may be driven by an electromechanical actuator which actuatormay be a galvanometer or a piezoelectric element.

A component comprising features made by any method disclosed and claimedhere is part of the invention such as components where the features areholes for nozzles for aerosolization. The component may be nozzleshaving exit apertures from about 0.1 micrometer to about 10 micrometerin diameter.

Another aspect of the invention is a component with a multiplicity offeatures on it which component has been produced by a method asdescribed above or claimed in the claims. The component may be a nozzlewhich is comprised of a thin sheet of material used for aerosolizationof a pharmaceutically active formulation. The nozzles produced may haveexit apertures having a diameter of from about 0.1 micrometers to about10 micrometers. The nozzles may have exit apertures from about 0.4micrometers to about 1.4 micrometers.

Another aspect of the invention is a nozzle fabricated from a two-stepprocess as described herein. The first step may comprise the applicationof pulses of largely the same energy to an aera where a feature is to becreated. A predetermined number of pulses may be delivered. Thereafter,the second step comprises delivering pulses of largely the same energyto the same area where the pulse features are to be created until afeedback circuit determines that the fabrication is complete.

In accordance with the above method of fabricating the nozzle the pulseof energy used in step 1 may be used in a range 0.1 to 3.0 uJ and thepulses in the first step may be from 1-100 and the pulse energy used inthe second step may be in the range of 0.5 to 3.0 uJ.

In accordance with the above nozzle fabrication method in two steps afeedback circuit may be used for measuring the transmitted power throughthe sheet where the holes are being formed to create the nozzle. Thefeedback may trigger termination of the process when the energy pulsetransmitted is 0.1 picojoule to 10 nanojoule. Alternatively, thefeedback circuit may terminate the process when the energy per pulse isdetermined to be in a range of 1-1,000 picojoule. Still further, thefeedback circuit may be designed to terminate the process when theenergy determined at a feature is in a range of 10-200 picojoules perpulse. Still further, the two step process of the invention may becarried out where the energy pulse in step 1 is 1:0.5-2.5 uJ and pulsesin the first step are in the range of 5-50 and the energy per pulse isin the range of about 22:0.1-1.0 uJ.

The two step process for producing the nozzles as described above may becarried out so that the exit diameter of the nozzle is less than about10 micrometers or less than about 2.5 micrometers or less than 1micrometer.

These and other aspects of the invention will become apparent to thosepersons skilled in the art upon reading the details of the formulationsand methodology as more fully described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in conjunction with the accompanying drawings. It isemphasized that, according to common practice, the various features ofthe drawings are not to-scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.Included in the drawings are the following figures:

FIG. 1 is a schematic drawing of an embodiment of the present inventionusing spatial multiplexing with an AOD and a multi element detector forfeedback control.

FIG. 2 is a schematic drawing of another embodiment of the presentinvention utilizing a spinning polygon with scan detector on the primarybeam to scan the beam repeatedly over a series of holes to be drilled.

FIG. 3 is a schematic drawing of another embodiment of the presentinvention utilizing a spinning polygon mirror with scan detector on anauxiliary beam to scan the beam repeatedly over a series of holes to bedrilled.

FIG. 4 is a schematic drawing of another embodiment of the presentinvention utilizing an oscillating mirror with scan detector on theprimary beam to scan the beam repeatedly over a series of holes to bedrilled.

FIG. 5 is a schematic drawing of another embodiment of the presentinvention utilizing an oscillating mirror with scan detector on anauxiliary beam to scan the beam repeatedly over a series of holes to bedrilled.

FIG. 6 is a schematic drawing of another embodiment of the presentinvention utilizing an acousto-optic element to scan the beam repeatedlyover a series of holes to be drilled.

FIG. 7 is a schematic drawing of another embodiment of the presentinvention utilizing an acousto-optic element with scan detector on theprimary beam to scan the beam repeatedly over a series of holes to bedrilled.

DETAILED DESCRIPTION OF THE INVENTION

Before the present formulations and methods are described, it is to beunderstood that this invention is not limited to particular formulationsand methods described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present invention will be limited onlyby the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the invention. The upper and lower limits of these smaller rangesmay independently be included or excluded in the range, and each rangewhere either, neither or both limits are included in the smaller rangesis also encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included in the invention.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. All publications mentioned herein areincorporated herein by reference to disclose and describe the methodsand/or materials in connection with which the publications are cited.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “aformulation” includes a plurality of such formulations and reference to“the method” includes reference to one or more methods and equivalentsthereof known to those skilled in the art, and so forth.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

DEFINITIONS

The terms “acousto-optic modulator,” “acousto-optic element,”“acousto-optic Deflector”, “AOD”, “AOM”, and the like are usedinterchangeably and will be interpreted herein to be an optical elementthat can be excited with acoustic (pressure) waves in order to diffractthe light that traverses the element. Essentially constant frequenciescan be used to create single beams that are diffracted into knownangles, or more complex frequency spectrums, such as multiple closelyspaced frequencies, harmonics, or more complex excitation signals can beused. The amplitude of the excitation can control the fraction of thelaser light being deflected, and the amount of LASER energy in thesingle beam(s). Two dimensional patterns can be created with twodimensional excitations, or by using multiple acousto-optic elements.Additional multiplexing can be achieved by utilizing higher orders ofdiffracted beams. Many materials can be used for the optical element,although preferred materials are quartz crystals and TeO₂.

An acousto optic element may comprise optically transparent acoustooptic medium having light incoming plane, light outgoing plane facinglight incoming plane, transducer joining plane, and inclined planetilted to transducer joining plane and piezoelectric transducer on whichtwo opposing planes i.e., electrode layers and are formed and thetransducer is connected to transducer joining plane of acousto opticmedium through one of the electrode layers, wherein a deposited layer ora coating layer is formed on at least one of ultrasonic transducer orthe acousto optic medium, the layer preventing ultrasonic wavesgenerated by oscillation of ultrasonic transducer leaking onto acoustooptic medium as a leakage-ultrasonic wave and propagating there, thusobtaining a high light-fading ratio as shown in U.S. Pat. No. 7,054,055which is incorporated herein by reference.

The terms “galvanometer”, “galvo” and the like are here usedinterchangeably and will be interpreted to mean an electrical means ofrapidly and accurately moving an optical mirror from one position to asecond position. Although classically a galvanometer is moved through afixed angle by the force of a current through a coil acting on a magnetattached to the mirror, many ways of actuating the mirror can beimplemented, including piezo actuators.

The term “LASER” and “LASER beam” and the like are used interchangeablyand will be interpreted to be any source of electromagnetic radiationwhich is essentially monochromatic or comprises essentially a frequencyof electromagnetic radiation and some harmonics or sub-harmonics.Examples of LASERs include but are not limited to Excimer LASERs, gasLASERs (including Helium-Neon, Argon, and CO₂ LASERs), YAG and YLFLASERs, frequency multiplied YAG and YLF LASERs (including frequencydoubled, tripled, and quadrupled versions), diode lasers, and fast,ultrafast, short-pulse and ultra-short pulse LASERs. It will be obviousto one skilled in the art that other directed energy sources could oftenbe used in place of a LASER system, and disclosure of processes where aLASER is used as an example should be considered to include these otherenergy sources.

The term “closed-loop”, “closed loop feedback” and the like are usedinterchangeably and will be interpreted herein to apply to a processthat is modified or terminated based on information about the progressor state of the process. This is in contrast to a process that is run“open-loop”, e.g. when a hole is drilled with a specific number ofpulses of a specified energy per pulse. The analogous closed-loopdrilling process might be when a hole is drilled with a multiplicity ofpulses of a specified energy and the drilling is terminated not at aspecific number of pulses but when a certain amount of the energy from apulse is detected having penetrated the material being drilled. In thepreferred embodiment, a hybrid method is used, wherein the part isprocessed for a fixed number of pulses, and then a property of theenergy source is changed, for example the energy per pulse, and then thefeature is completed using the feedback method.

The terms “detector”, “light detector” and the like are usedinterchangeably and will be interpreted herein to be any device used tomeasure any property of incident light, including but not limited toenergy, power, amplitude, phase, polarization, wavelength, beam width,radius of curvature, coherence, or propagation direction. Examples ofdetectors include array detectors such as CCD arrays, single elementdetectors such as semi-conductor, photo-multiplier tube, micro-channelplate, bolometer, pyroelectric or thermoelectric detectors, or otherdevice or material. Although it is preferable that the detector convertincident energy into electric current, it could also be possible to usemechanical means or other means of controlling process parameters basedon properties of incident light.

The terms “spinning polygonal mirror” and the like shall mean astructure with at least 2 non co-planar reflective surfaces that iscaused to rotate in a substantially uniform manner. Preferably thesurfaces are aligned such that as a LASER beam ceases to be incident ona first surface, and becomes incident on the next surface, due to therotation, the reflected beam is caused to traverse substantially thesame path as while the beam was incident on the first surface. Multiplerows of facets, or multiple beams incident on a single row from multipledirections, can be used to simultaneously fabricate multiple rows offeatures.

General Overview

The invention provides a method of more rapidly machining multiple,preferably similar or nearly identical, features using a LASER machiningsystem. During LASER machining, light of a wavelength and intensity thatwill modify the workpiece to be machined is directed at the workpieceand interacts to produce the desired change. If several features are tobe machined, the processing speed can be increased by processing amultiplicity of features simultaneously, increasing the incident power,increasing the pulse repetition rate, or increasing the rate at whichthe LASER beam is moved from one feature or group of features to thenext. In one embodiment of the invention, this is achieved by separatingthe LASER beam into multiple beams and machining the desired featuressimultaneously (FIG. 1). To achieve the characteristics desired of thefeatures in these cases, an array (500) of detectors (510) or an arraydetector (500) can be used to monitor the process on individual featuresor subgroups of features (410) and to modify the process to ensure thedesired results. Alternatively, a single detector (500) may be used. Inone embodiment, a number of pulses are directed simultaneously tomultiple locations on the target. The number of pulses can be apredetermined, fixed number, or can be based on a readout of thefeedback detector reaching a predetermined state or threshold. At thistime, the beam is delivered sequentially to at least some features,preferably to each feature individually, and at least one property ofthese at least some features is determined. Based on this determination,the process is modified, by changing at least one property of theincident light, or preferably, eliminating the power, delivered to asubset or all of the features, and the process may be iterated until allfeatures are determined to be adequately processed.

In another embodiment, the LASER beam is separated into multiplesegments in time and those segments are directed sequentially at themultiple features to be machined. The LASER beam can process a singlefeature until the processing is completed, and then be directed towardthe next feature. Alternatively the laser can be directed for toward asingle feature for a limited number, or preferably one, pulse(s). Thisembodiment has the advantage when there is some limit on the processingrates for the interaction of the LASER beam with the work piece. Oneexample of this is when a plasma plume results from the ablation ofmaterial from a surface subsequently blocking the machining LASER beam,and requiring that there be sufficient time allowed between pulses ofthe LASER beam for the plasma to dissipate. This embodiment also has theadvantage that the beam or target can be translated continuously,eliminating the time associated with acceleration, deceleration, andsettling. In this embodiment, one can unsure the quality of the featuresusing either an array of detection elements, which provide spatialresolution on the process, or preferably an individual detector, whichprovides temporally resolved data on the sequence of features beingdrilled. This information can be used to modify the process to ensurethat the individual features possess the characteristics desired.

In another embodiment, the LASER beam is directed at a single spot onthe target. The LASER beam micro-machines a feature, preferably a nozzlehole, more preferably a nozzle hole for aerosol drug delivery. When atleast one feature of the hole is determined to be sufficiently formed bya feedback detector, the LASER beam is very rapidly moved to theposition of the next feature in a row of features to be micro-machined.This is repeated until the entire row of features is complete. The beammay rapidly moved from one feature to the next using a variety oftechniques known to those skilled in the art, including but not limitedto stages, galvanometers, or preferably an acousto-optic modulator. Thefabrication may be completed by delivering a train of relativelyconstant energy pulses to the target, until the fabrication is stoppedbased on a measurement by the feedback detector. Preferably the energyof the pulses changes during the micromachining. The energy can changein a relatively continuous manner, can change in step wise fashion, orcombinations thereof. In a preferred embodiment, a fixed number ofpulses is delivered to the target material, the energy per pulse ischanged to a different, preferably lower, level, and then thefabrication is allowed to continue until the feedback detector signal isused to determine that at least one property of the feature, preferablythe size, has been met a pre-specified value. The amount of lighttransmitted depends strongly on the size and somewhat on the shape ofthe hole created, and thus holes of roughly the same shape and will bevery close to the same size if they were completed when they transmittedroughly the same amount of light. Holes drilled with this feedback mayhave standard deviation in hole size of only a few percent, comparedwith more than 10% for holes drilled without feedback. Once the row iscomplete, the beam, or the part, is moved to the position of the nextrow. Preferably this move is approximately perpendicular to the firstrow. This move can be accomplished by methods including, but not limitedto a stage, an acousto-optic modulator, or preferably a galvanometer.This process is repeated until the entire array has been fabricated. Inorder to minimize the time required to fabricate the array, a LASERrepetition rate of 30 kHz to 600 kHz should be used, preferably 60 kHzto 300 kHz, more preferably about 100 kHz. Use of high repetition ratesand rapid scan methods can lead to a time to fabricate the array offeatures of less than 25 milliseconds per feature, preferably less than10 milliseconds, more preferably less than about 3 milliseconds. Usingthe feedback method, it is possible to fabricate arrays comprisingnozzles with exit diameters less than about 10 micrometers, preferablyless than about 5 micrometers, more preferably less than about 2.5micrometer, still more preferably less than about 1 micrometer.

The AOD is driven with a radio frequency wave in the range of 10 MHz to1 GHz. A quartz AOD is preferably driven with a radio frequency wave inthe frequency range from 70 to 135 MHz. An AOD made with a TeO2 crystalmight also be used, in which case a synthesizer operating at lowerfrequencies (35-70 MHz) would be used.

If the move in the secondary, transverse direction is performed with thegalvanometer, a part with a few hundred holes, appropriate foraerosolization of pharmaceutical formulation for inhalation, typicallytakes 0.6-0.7 seconds to complete. If the stage is used to move in thetransverse direction, the slower move and settle time results indrilling times around 2.5 seconds, dominated by the stage movements. Ifthe stage is used to move the parts in both directions and the AOD isused only to modulate the energy per pulse in the appropriate sequence,parts take 20-30 seconds to complete, entirely dominated by the timerequired for hundreds of stage movements.

Nozzles can fabricated using a one step process, a two step process,more than two steps, or a continually varying pulse energy. In the onestep process, pulses of largely the same pulse energy are applied to thepart until the feedback system determines that the fabrication iscomplete. For the two step process, the first step preferably comprisesapplication of pulses of largely the same energy to the part for afixed, predetermined number of pulses. The second step comprisesdelivery of pulses of largely the same energy to the part until thefeedback circuit determines that the fabrication is complete. The twostep process has two advantages over the one step process. Firstly, thefabrication process is more rapid, as a large portion of the nozzle isdrilled rapidly at high power, only dropping to the smaller power todrill a very small, controlled exit hole. Secondly, the higher powerfirst step results in a larger diameter for much of the length of thenozzle, resulting in lower pressure required for aerosolization.

Single Step Process:

Pulse energy: about 0.1-3.0 uJ, or preferably about 0.2-1.5 uJ, or morepreferably about 0.45 uJ

Average pulses required: about 30-500, preferably 80-200, morepreferably 120-180

Energy per pulse transmitted at desired hole size: about 0.1 picojouleto 10 nanojoule, preferably 1-1000 picojoule, more preferably about10-200 picojoule.

Hole entrance size generated: 3-30 um, preferably, 6-20 um

Hole exit size generated: about 0.2-15 um, preferably 0.3-2 um, morepreferably 0.4-0.6 um

Two Step Process:

Pulse energy, step 1: about 0.1-3.0 uJ, preferably about 0.5-2.5 uJ,more preferably about l.5 uJ

Number of pulses, first step: about 1-100, preferably about 5-50, morepreferably about 10-30, most preferably about 20

Pulse energy, step 2: about 0.05-3.0 uJ, preferably about 0.1-1.0 uJ,more preferably about 0.15-0.5 uJ, most preferably about 0.2-0.25 uJ

Number of pulses, step 2: about 1-1000, preferably 10-500, morepreferably 30-200, most preferably 50-200

Energy per pulse transmitted to feedback detector at desired hole size:about 0.1 picojoule to 10 nanojoule, preferably about 1-1000 picojoule,more preferably 10-200 picojoule.

Hole entrance size generated: 3-30 um, preferably, 6-20 um

Hole exit size generated: about 0.2-15 um, preferably 0.3-2 um, morepreferably 0.4-0.6 um

The present invention can be used to fabricate arrays of pores in asheet of material. The material can be any material that can beprocessed by LASERs, including but not limited to metals, ceramics,glasses, and polymers. Many polymers can be used, including but notlimited to polyesters, polycarbonates, and polyetherimides. In thepreferred embodiment, the material is a polyimide film. The sheet canhave any thickness, but is preferably from about 10 μm to about 200 μm,more preferably from about 10 μm to about 50 μm, most preferably about25 μm thick. The pores to be formed using the present invention can haveany size and shape. For aerosolization nozzles, they have exitaperatures ranging from about 0.1 to about 50 micrometers, preferablyabout 0.3 to 10 micrometers in diameter. For pulmonary drug delivery,the exit aperatures will in general range from about 0.1 micrometer toabout 10 micrometer, preferably from about 0.3 micrometer to about 2.5micrometer, more preferably from about 0.4 micrometer to about 1.4micrometer in diameter. The pores can have any shape, including roughlyconical shapes, cylindrical shapes, or combinations thereof. In thepreferred embodiment, the pores are roughly conical, with the exit beingsmaller than the entrance. The exit of the pore can have any shape, butis preferably approximately circular.

The beams delivered to the sheet may have any radial shape including butnot limited to substantially circular and may be characterized by anyappropriate profile including but not limited to roughly gaussian ortop-hat profiles. Any suitable number of pores or holes may be formedincluding from a few holes to several hundreds or more.

In a first embodiment (FIG. 1) a LASER (100) generates a LASER beam(800) which flows through optics (200). The beam (800) may be directedby a mirror (210) to a beam splitter (300). The plurality of individualLASER beams (810) then flow through a lens (220) before being directedat individual features (410) of a component (400) which is beingmachined. The features (410) may be holes being drilled in a component(400) which is a sheet, preferably a polymer membrane. The controller(700) repeatedly actuates the LASER (100) sending rapidly repeatingLASER pulses at the features (410). In this embodiment the pulses arerepeated until the detector (500) with special detection components orspecial resolution features (510) detect the transmitted LASER pulses(820). The detectors output is measured by analyzer (600) which providesinformation to the controller (700) to turn off or modify the output ofthe LASER (100) or the AOM drive electronics (305).

The beam splitter (300) can be reconfigured during operation in how itdirects the beams (810). In this embodiment of the invention, thecontroller (700) causes the LASER to pulse repetitively until all of theholes (410) are completely drilled. In this embodiment of the invention,the detector (500) must have spatial resolution (510) to determine whenindividual holes are complete. The analysis apparatus (600) analyzes thespatial data to determine which holes have drilled through sufficiently.The synchronizing controller (700) uses the output from the analysisapparatus to control the beam splitter so that no beams are directed atholes that have been determined to be complete.

In this embodiment of the invention the beam splitter (300) may beimplemented as an acousto-optic modulator driven at a multiplicity offrequencies to split the beam. This may be implemented to create aneither one or two dimensional array. Two dimensional arrays are achievedby driving the acousto-optic element in two dimensions, or by using twoseparate acousto-optic elements, one rotated, preferably by 90°,relative to the other. The detector (500) may be a charge-coupled-deviceor similar imaging detector. The analyzer (600) may be a hardwiredanalog processor, a hardwired digital processor, or a programmableprocessor (including a computer). The synchronizing controller (700) maysimilarly be hardwired or a programmable processor.

In a preferred embodiment, the beam-splitter (300) is an acousto-opticmodulator (AOM) driven by a programmable frequency generator (305). Thedetector (500) is an imaging charge-coupled device (510) which providesa read out signal which is analyzed by a computer and the computer alsoperforms the synchronization with the programmable frequency generatorto control the beamsplitter (300).

In another embodiment of the invention, a LASER scanner repetitivelydirects pulses from a LASER beam (100) at a sequence of features (410)to be machined. The detector (500) resolves the response of the systemin time, and the output of the detector (500) is analyzed insynchronization with the controller (700) and LASER device (100) todetermine which response corresponds to which feature. Thesynchronization controller (700) causes the LASER device (100) to omitpulses directed at those features that are determined to have beencompleted.

FIGS. 2 and 3 show another embodiment of the invention wherein the LASERbeam (800) is directed from feature to feature by a spinning polygonalmirror (310). An electrical photo-detector (520) detects the LASER light(820) transmitted through an opening or feature (410) once it isdrilled. An analyzer (600) determines whether the pulses detected areenergetic enough to indicate that the corresponding hole (410) issufficiently drilled. A synchronization controller (700) omits the LASERpulses corresponding to completed holes from subsequent sequences ofLASER pulses.

In this version of this embodiment, a detector (320) may be used tosynchronize the LASER pulse sequence and the detected signals with therotation of the mirror (310). The detector (320) may be substituted withor supplemented with an encoder on the rotating assembly of the mirror(310). The detector (32) is preferably an optical detector that detectsthe LASER beam used for machining or an auxiliary beam generator (330)that is also reflected off of the polygonal mirror (310).

In another embodiment (FIGS. 4, 5), the LASER beam (800) may instead bescanned from feature to feature using an oscillating mirror (340). Inthis version, the mirror may be a galvanometer (340). Independent of themethod of driving the mirror (340), in this version the LASER pulses,detected pulses, and mirror position may also be synchronized by anencoder (optical detector 320) or detecting the machining or anauxiliary beam generator (330).

Also in the embodiment where the LASER beam is scanned from feature tofeature, the LASER beam may instead be scanned from feature to featureusing an acousto-optic element (300) as shown in FIGS. 6 and 7 which isdriven at a continuously or discretely varying frequency. In thisversion, the LASER pulses, and beam position may be synchronizeddirectly with the beam position drive signal or by optically detectingthe scanned beam. For the highest level of reproducibility, the LASERpulses and the excitation signal to the acousto-optic element may bephase locked. The acousto-optic modulator may direct only one LASERpulse to the feature (410) before redirecting the beam to the nextfeature. In another embodiment, the acousto-optic modulator directpulses at a single feature (410) until the analyzer (600) determinesthat the feature is complete, and the AOM (300) directs the LASER beamto the next feature to be processed. AOM (300) may be a two dimensionalAOM, or two one dimensional AOM. Alternatively, AOM (300) may be a onedimensional AOM, and once a linear array of features have beenprocessed, the part (400) is moved to another position by a stage. Inthe preferred embodiment, AOM (300) is a one dimensional AOM, and once alinear array of features have been processed, mirror (210) is moved to anew position, allowing the fabrication of a new linear array offeatures. Mirror (210) can be moved using any of a number of methods,but in the preferred embodiment, mirror (210) is a galvanometer.

One skilled in the art reading this disclosure will understand that anyof a number of techniques can be used to scan the beam. It will also beunderstood that further multiplexing of the beam could be achieved in anumber of ways, including using multiple LASERs, using diffractiveelements, beams splitters, or the like.

In any version of the embodiment in which the LASER beam is scanned fromfeature to feature and the detector resolves the system response intime, the detector may be, but is not limited to, an optical detectorwhich detects the transmitted LASER light from the machining beam, anoptical detector that detects auxiliary light applied to probe the stateof the process, an optical detector that detects some secondary lightgenerated by the process, or an electrical detector that detects someaspect of the process.

In the embodiment of FIGS. 6 and 7 the detector (520) may be ahigh-speed semiconductor detector with a narrow-band optical responsethat converts the incident detected light into an electrical signal withvoltage proportional to the energy in the light. This kind of detectormay be used by combining a narrow-band optical filter with a sensitive,high-speed photo-diode read out by a transresistance orcharge-integrating amplifier.

In any version of the embodiment in which the LASER beam is scanned fromfeature to feature and the detector resolves the system response intime, the analysis apparatus (600) may be a data acquisition unitfeeding data to a microprocessor or computer for subsequent analysis ofthe data using computer software, or it may be a hardwired circuit thatcompares the detector output to a threshold condition and has logic thatgates the pulses in the sequence, blocking those that correspond tofeatures that have already achieved the threshold condition.

The embodiment of FIGS. 6 and 7 the analyzer (600) may be a hardwiredcircuit with a comparator that triggers when the detector output risesabove a threshold voltage. The output of the comparator is used toconditionally disable the inputs of series gates that control thetransmission of each of the pulses in the repeating series correspondingto the individual features. As the gates are disabled, they cease totransmit the pulses corresponding to that feature until reset formachining the next series of features. In a preferred embodiment, ratherthan ceasing to transmit the pulses, the laser beam is scanned to thenext position that requires a pulse.

In the embodiment wherein the beam is scanned from feature to feature byusing an acousto-optic element (300), the controller (700) can, based onresults from the analyzer (600), cause the acousto-optic elementelectronics (305) to modify the excitation to acousto-optic element(300), for example by modifying the frequency, amplitude, phase,frequency width, spectrum etc. of the signal associated with a feature,or skipping the excitation associated with a feature entirely if thatfeature is determined to be fully processed.

In any version of the embodiment in which the LASER beam is scanned fromfeature to feature and the detector resolves the system response intime, the synchronization controller (700) may include a trigger thatsynchronizes the start of the series of LASER pulses with the start ofthe scan by the scanning apparatus, a pulse series generator with stabletiming relative to the scan position of the scanning apparatus,conditional LASER pulse generation depending on previous detector data,and a reset mechanism that terminates pulse generation after (a) a givennumber of pulses or (b) completion of some number of features asdetermined by the detector information, or any other control featuresand methodologies.

In a preferred embodiment, the synchronization controller includes thededicated gates described as part of the analyzer apparatus, circuitryto repeatedly generate the pulse sequence based on a frequencystabilized oscillator and a trigger based on a beginning of scan signalfrom the LASER scanner.

In a final embodiment of the invention, the LASER beam is scanned fromfeature to feature and the detector is an array which detects the statusof each of the elements. The detector may be an imaging or non-imagingdetector that is sensitive to the light transmitted from the drillingoperation of each feature, or may be some other detector with an arrayof elements used to monitor the different features to be machined. Thisembodiment may require calibration of the individual elements of thedetector to allow the threshold to be set correctly for each one, orconversely, appropriate thresholds may need to be determined for eachelement.

EXAMPLES

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the present invention, and are not intended to limit thescope of what the inventors regard as their invention nor are theyintended to represent that the experiments below are all or the onlyexperiments performed. Efforts have been made to ensure accuracy withrespect to numbers used (e.g., amounts, temperature, etc.) but someexperimental errors and deviations should be accounted for. Unlessindicated otherwise, parts are parts by weight, molecular weight isweight average molecular weight, temperature is in degrees Centigrade,and pressure is at or near atmospheric.

Example 1

In this example, a single-hole LASER drilling process was developedbased a 5 kHz LASER pulse rate, and a higher processing speed wasdesired. Later, a LASER with a 100 kHz pulse rate became available.Rather than increasing the pulse rate on a single feature, the beam canbe scanned repeatedly across the work piece at 5 kHz or less using anoscillating mirror (340, FIGS. 4 and 5). The LASER pulses aresynchronized with the oscillation of the mirror using a detector (320)with a narrow slit covering the sensitive surface, placed next to thepart to be machined. As the beam scans across the slit, the LASER (100)is triggered to pulse in high-energy mode, so that high energy pulsesare repeatedly directed to the same set of sequential locations (410).In this way, each of 20 or more different locations are each exposed to5 kHz or less drilling operations using a single 100 kHz LASER. In thepreviously developed process, the drilling on a single hole isterminated when a certain amount of LASER processing light istransmitted through the hole after it completely penetrates thematerial. This light is detected, read out and analyzed by an opticaldetector (520), an electrical threshold detector, and a logic circuit.To retain the closed-loop feedback characteristic of the process, theoptical detector and electrical threshold detector are monitored by aseries of logic circuits, with the LASER pulses, motion of the mirror,detector output, and activation of the logic circuits all synchronizedto correspond to the sequential locations. Each of the logic circuitscan omit any LASER pulses directed at its corresponding featuresubsequent to detection of a threshold amount of light being transmittedthrough that feature. Thus, the process as previously developed isapplied to each feature, but the rate of processing is greatlyincreased.

Example 2

In this example, a single-hole LASER drilling process was developedbased on a 5 kHz pulse repetition rate, and a higher processing speedwas desired. In order to drill many holes at once, the LASER beam can besplit into many beams using an acousto-optic modulator. This splittingcan be in one or two dimensions, but one dimensional splitting issimpler and easier to explain and is used in this example (FIG. 1). Eachbeam (810) is formed by the incident LASER beam (800) interacting with adensity variation in the acousto-optic element (300). The densityvariation results from a sound wave typically generated by driving theacousto-optic element with an electrical signal of an appropriatefrequency. Thus each beam corresponds to a frequency and the beamintensity can be adjusted by adjusting the amplitude of the electricalsignal at that frequency. All of the signals are combined electricallyand applied to the acousto-optic element to generate all of the beams atonce. In the previously developed process, the drilling on a single holeis terminated when a certain amount of LASER processing light istransmitted through the hole after it completely penetrates thematerial. This light is detected, read out and analyzed by an opticaldetector, an electrical threshold detector, and a logic circuit. Toretain the closed-loop feedback characteristic of the process, a linearhigh speed CCD array detector (500) monitors the light transmittedthrough the material. The array is read out and an analysis circuitdetermines whether the light, detected by the elements corresponding tothe individual holes (410) to be drilled, has reached threshold. Whenthe light corresponding to a hole does reach threshold, the signalamplitude at the frequency generating the beam machining that hole canbe reduced or switched off. Once enough of the holes have been drilled,the LASER pulsing is stopped and the machining on that part is complete.Although in this example, each beam is associated with a singlefrequency, it will be obvious to one skilled in the art that morecomplex features can be machined, or better control maintained, by usingmore complex excitation signals.

Example 3

In this example, 10 holes are drilled at once using a laser pulsing at100 kHz and directing each pulse sequentially at the 10 holesconsecutively. The system described above can be used, but with thesynthesizer driving the AOD reprogrammed to multiplex the pulses to the10 holes in time, —using the same pre-programmed sequence for each one.The synthesizer then synchronizes with the laser pulsing and thedetector response, tracking which of the 10 holes has been processed tocompletion and skipping those holes. In either case, the synthesizerreturns control to the next level controller in the system once it hascompleted drilling the 10 holes.

Example 4

In this example, the LASER was a Coherent Avia 355-7000 pulsing at 100kHz on its internal clock, although repetition rates as low as 5 kHzhave been used and higher rates (300 kHz or more) may be desirable. TheLASER beam was transported and conditioned by a 5:6 beam expander andspatial filter with 134 mm incident focal length and 25 um pin hole. Thebeam passed through an Isomet quartz D1129-XY acousto-optic deflector(AOD) and was reflected off of a GSI Lumonics FM3 galvanometer. A final134 mm focal length projection lens imaged the spot onto the workpiece,which was placed on an automated stage (Aerotech ALS130-100-LTAS withU511 controller). A control computer initiated drilling by triggering anIsomet iDDS, a programmable synthesizer that drives the AOD, and enabledlaser pulsing. The iDDS synchronized with the laser pulsing and bothmodulated the energy in and directed each laser pulse appropriately todrill 10 holes, although as few as a single holes and as many as 50 havebeen used, in sequence, in a 25 micrometer thick polyimide sheet. Eachhole was drilled with a sequence of pulses of varying pulse energy, in apattern pre-loaded into the iDDS. Nozzles were fabricated using a twostep process. For the two step process, the first step comprisedapplication of pulses of largely the same energy to the part for afixed, predetermined number of pulses. The second step compriseddelivery of pulses of largely the same energy to the part until thefeedback circuit determined that the fabrication was complete. Thepolyimide sheet is highly opaque at the 355 nm laser wavelength, andthus 355 nm radiation only began to propagate beyond the membrane once ahole had been formed. The transmitted light passed through a narrow-bandfilter, which excluded other light generated by fluorescence and plasmaemission during the drilling, and fell on an HUV-4000B detector (EG&GCanada) bypassed by a 60 picofarad capacitor and a 60 kilo-ohm resistor,generating an electrical signal proportional to the amount of lightenergy in each transmitted pulse and short enough to resolve theresponse to individual pulses. Once the amount of light transmitted perpulse, and thus the electrical signal, reached a certain thresholdlevel, the drilling at that location was terminated, the frequency usedto excite the AOM crystal was incremented, moving the beam to the nextposition, and the sequence was begun for the next hole. After 10 holeswere complete (approximately 10-20 ms processing time), the iDDSsynthesizer signaled the control system, and t the beam or the part wasdeflected by in a transverse direction so that the next 10 holes couldbe drilled adjacent to the previous set. This was repeated until 340holes were created, in a 10×34array, and this entire process wasrepeated several hundred times to make a lot of nozzle arrays. One lotwas fabricated using the stage for the transverse movement, resulting ina fabrication time per nozzle of 2.7 seconds. A second lot wasfabricated using the galvo for the transverse movement, resulting in afabrication time of less than 1 second per nozzle.

Energy per pulse, step 1: 1.5 uJ

Pulses in the first step: 18

Energy per pulse, step 2: 0 0.25 uJ

Pulses in the second step were found to range from 100-200 pulses.

The feedback circuit terminated the process when a predefinedtransmitted energy of about 60 picoJoule/per pulse was achieved.

In this example, nozzles fabricated using the stage had an average exithole diameter (area equivalent diameter of the hole, as determined bySEM) of 559 nm.

The hole-to-hole diameter standard deviation within a nozzle was 15-30nm. The standard deviation, between different arrays in the sameprocessing batch, of the average exit hole size of each array was 8 nm.The standard deviation, over many processing batches, of the averagehole size of each processing batch is typically between 10 and 30 nm.The time required to fabricate a nozzle array was 2.7 seconds. With theAOD and galvo, drill time was just under 1 second. The average hole sizewas 595 nm, with a 30 nm standard deviation. The aerosols generatedusing these nozzles had particle sizes with volume median diameters inthe range of 3-4 um, typically around 3.5 um. The standard deviation,between different arrays in the same processing batch, of the averageexit hole size of each array was 12 nm. In an experiment using an allmechanical mass-production device, emitted doses were 60% of thepackaged dose, with 4% standard deviation. On an optimized researchdevice, the emitted doses were 73% with a 1.5% standard deviation,indicating that the nozzles themselves are of very high quality.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto.

1. A method of machining, comprising: sequentially applying energy to amultiplicity of areas where a feature is to be machined; and repeatingthe sequential application of energy to the areas thereby allowing amultiplicity of features to be machined at essentially the same time. 2.The method of claim 1 wherein the energy applied is generated by aLASER.
 3. The method of claim 2, wherein the LASER is directed from onearea to another area by an element chosen from a spinning element, avibrating element, and an oscillating element; the method furthercomprising: detecting energy directed at the areas; and evaluatingfeature formation based on detected energy. 4-12. (canceled)
 13. Themethod of claim 3, further comprising: terminating application of energybased on evaluated energy at the multiplicity of areas totaled together.14. The method of claim 3, further comprising: terminating the energy atindividual areas based on energy evaluated at individual areas.
 15. Themethod of claim 14, wherein a LASER beam applies the energy, an opticalelement with time-varying characteristics redirects :sequential temporalsegments of the LASER beam to the multiplicity of areas to be machined,a detector detects a level of machining on each area individually, andan electrical system controlling the LASER eliminates temporal segmentsof the LASER beam that would have been directed at features for whichthe machining has been determined to be complete.
 16. The method ofclaim 15, wherein tile detector is a photo-detector that detects theamount of machining LASER light that is transmitted through thefeatures, and completeness is determined by comparing a peak intensityor total energy of light in a transmitted pulse to a threshold value.17. A method of machining, comprising the steps of: spatially separatinga beam of energy into a multiplicity of individual energy flows;directing individual energy flows at a multiplicity of areas to bemachined; evaluating a degree of completion of the machining ofindividual features at the areas, wherein the separation of the energyis modified to most effectively complete the machining of themultiplicity of features.
 18. The method of claim 17, wherein the beamof energy is a LASER, the LASER beam is separated into a multiplicity ofbeams by an acousto-optic modulator driven at a multiplicity offrequencies, a detection system monitors the individual areas beingmachined into features, and the drive signal controlling theacousto-optic modulator is modified to achieve the desired machining ofthe areas into features.
 19. The method of claim 18, wherein the beamdirected at a particular area is eliminated or redirected when the beamhas completed formation of a feature.
 20. The method of claim 19,wherein the detector is an array detector, and the transmitted power ismonitored simultaneously at each area where the beam is directed. 21.The method of claim 19, wherein the detector is a single detectorcapable of measuring transmitted power at the multiplicity of areas as awhole by a method comprising: (a) directing a plurality of pulsessimultaneously to multiple areas on a target; (b) directing the beamsequentially to each feature; (c) determining at least one property ofeach feature; and (d) modifying the method based on the at least oneproperty determined in (c).
 22. The method of claim 21, wherein themodifying in step (d) comprises eliminating power delivered to a subsetof the features, and steps (a)-(d) are repeated until all features aredetermined to be machined to a desired end point. 23-26. (canceled) 27.A method of LASER machining a component, comprising the steps of:creating a LASER beam from a LASER device; focusing the LASER beam on asurface of a mirror; and changing the angle of the mirror so as todirect the LASER beam to features of a component to be machined;detecting energy from the reflected beam on the features; analyzingenergy detected and creating a signal based on the analysis; and sendingthe signal to the device which controls the LASER beam to therebycontrol machining of the component with the LASER beam.
 28. A system formicro-machining an array of nozzle holes in a sheet of material, thesystem comprising: a LASER; a system for moving a beam of the LASERrapidly in a first direction; a feedback detector that detects at leastone property of the LASER light while the LASER creates the nozzle holesin the sheet of material; wherein the array of nozzle holes comprisesnozzle holes having exit diameters of less than about 10 micrometers.29. The system of claim 28, wherein the laser is chosen from a YAG LASERand a YLF LASER.
 30. The system of claim 28, wherein the LASER is afrequency tripled YAG LASER.
 31. The system of claim 28, wherein thesystem for moving the beam rapidly in a first direction is chosen froman acousto-optic modulator and a galvanometer.
 32. The system of claim28, wherein the system for moving the beam rapidly in a first directionis an acousto-optic modulator.
 33. The system of claim 28, furthercomprising a system for moving the beam rapidly in a second direction.34-51. (canceled)